HALF MOON BAY (KRON) — Authorities in San Mateo county said they have identified a man who may have been swept out to sea from Half Moon Bay.

The San Mateo County Sheriff’s Office believes that 25-year-old Michael Dwyer of Brisbane may have been washed off-shore Monday afternoon.

A witness at the time reported seeing someone struggling in the surf. That call triggered a massive air and sea search that continued late into Monday evening.

Authorities were eventually able to identify Dwyer when his family called to report that he had not returned home.

Dwyer’s Jeep Wrangler was also found in a parking lot near the beach where he may have disappeared.

Following a brief search Tuesday morning, the effort to find Dwyer was called off.

Around 1:30 p.m. Monday, a witness reported seeing a man entering the water near Dunes Beach located on Young Avenue, according to the sheriff’s office.

The witness reported that the person had been swept out to sea by ocean currents and never came out of the water, sheriff’s spokesman Sal Zuno said.

The report prompted an extensive air and sea search involving a helicopter, two lifeboats and various law enforcement units. The search continued until about 7 p.m., according to the U.S. Coast Guard.

Sheriff’s officials cannot confirm the man seen entering the water is Dwyer and are continuing to search on land for the vanished swimmer, according to Zuno.

Anyone with information about Dwyer’s disappearance or Monday’s incident is asked to contact the San Mateo County Sheriff’s Office at (650) 363-4911. Callers who wish to remain anonymous can call (800) 547-2700.